While other major causes of death continue to experience decline, those from AD continues to rise. In 1991, only approximately 14,000 death certificates recorded Alzheimer's disease as an underlying cause. In 2006, it was noted that there was an increase of approximately 46% in which Alzheimer's disease was listed as the direct cause of death. This is significant when compared to the present leading cause of death, heart disease, which decreased by 11% in the same time.